FROMLIST: mfd: cros_ec: Allow building for ARM64

FROMLIST: mfd: cros_ec: Allow building for ARM64

There are platforms using the ChromeOS embeded controller on ARM64 now,
so let's allow using this driver (without having to use COMPILE_TEST).

Signed-off-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
BUG=none
TEST=make sure we can enable cros_ec for ARM64

Change-Id: I828fec4a2022ea50f10c269ee88ae92c30f48337
Reviewed-on: https://chromium-review.googlesource.com/339540
Commit-Ready: Dan Shi <dshi@google.com>
Tested-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: Guenter Roeck <groeck@google.com>
Reviewed-on: https://chrome-internal-review.googlesource.com/256311
Commit-Ready: Brian Norris <briannorris@google.com>
Tested-by: Brian Norris <briannorris@google.com>
Reviewed-by: Doug Anderson <dianders@google.com>
Signed-off-by: Caesar Wang <wxt@rock-chips.com>